Neck Pain: Back-sleeping is often said to be the best position for neck pain.  Back-sleeping can actually increase neck discomfort when using a pillow that is too thick(causes the head to flex forward) or too thin(causing the head to flex backward) 

Back-sleepers: Use a pillow that keeps the neck in a neutral position, in line with the spine.  When viewed from the side, the ear should be in line with the shoulders or slightly above them. Attempt to maintain a level head position with the chin level to the sternum

Side-sleepers:  Add a thin pillow or a rolled-up bath towel between the neck and the mattress in addition to your regular pillow to provide neck support and prevent the spine from bending to either side.

Stomach-sleepers:  This position is the worse for neck pain because you will need to turn your head to one side or the other, which places strain on the neck.  It is best to try another position, if possible.

You can change how you sleep: When you get into bed, start in the position in which you would like to sleep. Then spend a minute visualizing yourself staying in this position for the night.  If you wake up and are out of  position, calmly go back to the position you are trying to change to.  In most cases, good progress can be made in four to six weeks, it is something you will need to keep working on to improve. It is very easy to fall back into old habits.

Low-Back Pain:

Back-sleepers: Many people remark that their backs feel better when they sleep on their backs, particularly if they use a pillow or two to slightly 

elevate the knees. However, side-sleeping often feels more natural

Side-sleepers:  Lie on one side in a “stacked” position, with your 

shoulders, knees and hips in a up-and-down alignment with knees slightly bent.Helpful: Place a pillow between your knees. This helps to prevent the top leg from rolling over the bottom, which can twist the spine.

Stomach-sleepers:  This position can strain your lower back.  If you find it difficult to try the positions above, place a pillow under your stomach to 

reduce excessive spinal extension.

Hip Pain:

Back-or-stomach sleepers:  People with arthritis-related hip pain often have more pain when sleeping on their back or stomach.  Try side-sleeping with a small pillow under the knees(when lying on back) or under the 

stomach (when lying on your stomach).

Side-sleepers: Side-sleeping is usually best for arthritis-related hip pain.  Keep your knees slightly bent and use a pillow between the knees  and thighs to keep the hip in a more neutral position.  If lying on one side is more painful than the other, switch sides

KNEE PAIN:

With knee pain, back-sleeping can be painful because the knees are extended all night…But side-sleeping can cause irritation where the knees touch.

BACK SLEEPERS:

Try placing a pillow under the knees to prevent them from over-straightening.  Note:  This position can be painful for some people.

SIDE-SLEEPERS:

Sleep with a pillow between your knees or use cloth knee pads, turning them sideways so that the area where the knees touch is well padded.

STOMACH-SLEEPERS:

 This position can place  pressure on the knees. But if it is difficult for you to switch to back or side sleeping, put a pillow under your stomach to take some of the pressure off the knees.

You can change how you sleep: When you get into bed, start in the position in which you would like to sleep. Then spend a minute visualizing yourself staying in this position for the night.  If you wake up and are out of  position, calmly go back to the position you are trying to change to.  In most cases, good progress can be made in four to six weeks, it is something you will need to keep working on to improve. It is very easy to fall back into old habits.